Which of the following is the oldest?
Technically Sue the dinosaur is older, although the stereotype of librarians with buns is pretty close behind. ALA was "born" on October 6, 1876. For whatever it's worth, that makes us older than the IRS.

ALA puts on two conferences each year - "Midwinter" in January and "Annual" in June. How many individual sessions are there at Annual?
It's mind-boggling to think about it, but ALA's Conference Services Unit has to coordinate 2,500 meetings, even at the "smaller" Midwinter Meeting. That number can go as high as 2,800 at some Annual Conferences.

What was the most challenged book in libraries in 2006 as tracked by ALA's Office for Intellectual Freedom?
In 2006, 546 books were challenged in libraries across the U.S., but And Tango Makes Three topped the list.